Phenotypic trait changes in laboratory--reared colonies of the maize herbivore, Diabrotica virgifera virgifera.

The North American and European maize pest Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) was used to assess whether conditions of the natal field, subsequent laboratory rearing, or genetic population origin affect phenotypic traits of fitness, activity, or morphometrics. Standardized laboratory bioassays with large sample sizes revealed that none of the 16 tested traits, except crawling behaviours, appeared consistently stable across all seven tested colonies. Environmental conditions in the natal field of the F 0 generation affected trait averages of the subsequently reared F 1 generation in laboratory in ca. 47% of cases, and trait variability in 67% of cases. This was apparent for fitness and morphometrics, but less obvious for activity traits. Early generation laboratory rearing affected trait averages in ca. 56% of cases: morphometrics changed; fecundity and egg survival increased from F 1 to F 2. Trait variability increased or decreased in 38% of cases. Laboratory rearing for over more than 190 generations affected the trait averages in 60% of cases, reflected by decreases in flight activity and increases in body size, weight, and fecundity to some extent. It had little effect on trait variability, especially so for morphometric variability. The genetic population origin affected average levels of 55% and variability of 63% of phenotypic traits. A comparison among D. v. virgifera studies might be difficult if they use different populations or laboratory colonies. It is advised to consider possible effects of original field conditions, laboratory rearing, and population genetics when planning comparative studies targeting fitness, activity, or morphometric questions regarding Diabrotica species.

A comparison study of two different control criteria for the real-time management of urban groundwater works.

We present the comparison of two control criteria for the real-time management of a water well field. The criteria were used to simulate the operation of the Hardhof well field in the city of Zurich, Switzerland. This well field is threatened by diffuse pollution in the subsurface of the surrounding city area. The risk of attracting pollutants is higher if the pumping rates in four horizontal wells are increased, and can be reduced by increasing artificial recharge in several recharge basins and infiltration wells or by modifying the artificial recharge distribution. A three-dimensional finite elements flow model was built for the Hardhof site. The first control criterion used hydraulic head differences (Δh-criterion) to control the management of the well field and the second criterion used a path line method (%s-criterion) to control the percentage of inflowing water from the city area. Both control methods adapt the allocation of artificial recharge (AR) for given pumping rates in time. The simulation results show that (1) historical management decisions were less effective compared to the optimal control according to the two different criteria and (2) the distribution of artificial recharge calculated with the two control criteria also differ from each other with the %s-criterion giving better results compared to the Δh-criterion. The recharge management with the %s-criterion requires a smaller amount of water to be recharged. The ratio between average artificial recharge and average abstraction is 1.7 for the Δh-criterion and 1.5 for the %s-criterion. Both criteria were tested online. The methodologies were extended to a real-time control method using the Ensemble Kalman Filter method for assimilating 87 online available groundwater head measurements to update the model in real-time. The results of the operational implementation are also satisfying in regard of a reduced risk of well contamination.

Native range assessment of classical biological control agents: impact of inundative releases as pre-introduction evaluation.

Diadromus pulchellus Wesmael (Hymenoptera: Ichneumonidae) is a pupal parasitoid under consideration for introduction into Canada for the control of the invasive leek moth, Acrolepiopsis assectella (Zeller) (Lepidoptera: Acrolepiidae). Since study of the parasitoid outside of quarantine was not permitted in Canada at the time of this project, we assessed its efficacy via field trials in its native range in central Europe. This was done by simulating introductory releases that would eventually take place in Canada when a permit for release is obtained. In 2007 and 2008, experimental leek plots were artificially infested with pest larvae to mimic the higher pest densities common in Canada. Based on a preliminary experiment showing that leek moth pupae were suitable for parasitism up to 5-6 days after pupation, D. pulchellus adults were mass-released into the field plots when the first host cocoons were observed. The laboratory-reared agents reproduced successfully in all trials and radically reduced leek moth survival. Taking into account background parasitism caused by naturally occurring D. pulchellus, the released agents parasitized at least 15.8%, 43.9%, 48.1% and 58.8% of the available hosts in the four release trials. When this significant contribution to leek moth mortality is added to previously published life tables, in which pupal parasitism was absent, the total pupal mortality increases from 60.1% to 76.7%. This study demonstrates how field trials involving environmental manipulation in an agent's native range can yield predictions of the agent's field efficacy once introduced into a novel area.

Comparative life tables of leek moth, Acrolepiopsis assectella (Zeller) (Lepidoptera: Acrolepiidae), in its native range.

Leek moth, Acrolepiopsis assectella (Zeller) (Lepidoptera: Acrolepiidae), is an invasive alien species in eastern Canada, the larvae of which mine the green tissues of Allium spp. This study was designed to construct and analyse life tables for leek moth within its native range. Stage-specific mortality rates were estimated for the third leek moth generation at three sites in Switzerland from 2004 to 2006 to identify some of the principle factors that inhibit leek moth population growth in areas of low pest density. The contribution of natural enemies to leek moth mortality was measured by comparing mortality on caged and uncaged leeks. Total pre-imaginal mortality on uncaged plants was 99.6%, 99.1% and 96.4% in 2004, 2005 and 2006, respectively. Variation in mortality was greater among years than among sites. Total larval mortality was greater than that in the eggs and pupae. This was due largely to the high mortality (up to 83.3%) of neonates during the brief period between egg hatch and establishment of the feeding mine. Leek moth pupal mortality was significantly greater on uncaged than on caged leeks, indicating an impact by natural enemies, and this pattern was consistent over all three years of study. In contrast, the other life stages did not show consistently higher mortality rates on uncaged plants. This observation suggests that the pupal stage may be particularly vulnerable to natural enemies and, therefore, may be the best target for classical biological control in Canada.

Pacemaker infection with propionibacterium and a nephritic sediment.

Like any other implanted foreign body, the different parts of pacemakers (pulse generator pocket, epicardial or transvenous leads) can become infected. Staphylococcus aureus and coagulase-negative staphylococci are the causative organisms in most of the cases (65 â 75%), propionibacterium is described to be involved in only 1% of cases. This report describes a case of nephritic sediment in a young female patient with a pacemaker implantation 9 years ago because of a third degree atrioventricular block, in which a battery exchange was necessary 2.5 years ago. This young patient was referred from a nephrologist for renal biopsy because of a nephritic sediment and diffuse complaints including low-grade fever with a suspected underlying autoimmune disease. The laboratory examinations were all negative with the exception of a diminished C3 complement level. Blood cultures were positive for propionibacterium, but the microbiologists were considering it as a contamination. 11 more blood cultures collected thereafter were all positive and a transesophageal ultrasound revealed a small vegetation at 1 of the transvenous electrodes of the pacemaker. Because of a penicillin allergy she was treated with clindamycin, and the blood cultures were negative after a few days. After a full course (7 weeks) of antibiotic treatment the C3 complement level normalized and a series of 10 blood cultures remained negative 10 â 15 days after discontinuation of antibiotic therapy. Discussing all the differential diagnoses of a nephritic sediment combined with hypocomplementemia, positive blood cultures and a vegetation on a pacemaker electrode in the transesophageal ultrasound, the diagnosis of an immune complex glomerulonephritis due to a propionibacterium pacemaker infection needs no confirmation by renal biopsy.

Reversible light-dependent molecular switches on Ag/AgCl nanostructures.

Nanostructured Ag/AgCl substrates were used to generate reversible and highly efficient light-dependent chemical switches based on adsorbed 4,4'-dimercaptoazobenzene (DMAB). DMAB was formed in situ via laser-induced dimerization either from 4-nitrothiophenol (4-NTP) or 4-aminothiophenol (4-ATP). The subsequent reaction pathways of DMAB, however, were quite different as monitored by surface enhanced Raman spectroscopy. In the 4-NTP/DMAB system, AgCl catalyses the reversal of the dimerization. Conversely, irradiation of adsorbed 4-ATP first generated cis-DMAB attached to the surface via two Ag-S bonds, followed by AgCl-catalysed cleavage of one Ag-S bond and cis → trans photoisomerisation of DMAB. In the dark, the trans-isomer thermally reverts to cis-DMAB. The here presented light-dark chemical switches, which work without changing other parameters (e.g., pH, anaerobic vs. aerobic), are based on the (photo)catalytic properties of the Ag/AgCl substrate and do not function on pure metal surfaces.

Specificity in protein-protein interactions: the structural basis for dual recognition in endonuclease colicin-immunity protein complexes.

Bacteria producing endonuclease colicins are protected against their cytotoxic activity by virtue of a small immunity protein that binds with high affinity and specificity to inactivate the endonuclease. DNase binding by the immunity protein occurs through a "dual recognition" mechanism in which conserved residues from helix III act as the binding-site anchor, while variable residues from helix II define specificity. We now report the 1.7 A crystal structure of the 24.5 kDa complex formed between the endonuclease domain of colicin E9 and its cognate immunity protein Im9, which provides a molecular rationale for this mechanism. Conserved residues of Im9 form a binding-energy hotspot through a combination of backbone hydrogen bonds to the endonuclease, many via buried solvent molecules, and hydrophobic interactions at the core of the interface, while the specificity-determining residues interact with corresponding specificity side-chains on the enzyme. Comparison between the present structure and that reported recently for the colicin E7 endonuclease domain in complex with Im7 highlights how specificity is achieved by very different interactions in the two complexes, predominantly hydrophobic in nature in the E9-Im9 complex but charged in the E7-Im7 complex. A key feature of both complexes is the contact between a conserved tyrosine residue from the immunity proteins (Im9 Tyr54) with a specificity residue on the endonuclease directing it toward the specificity sites of the immunity protein. Remarkably, this tyrosine residue and its neighbour (Im9 Tyr55) are the pivots of a 19 degrees rigid-body rotation that relates the positions of Im7 and Im9 in the two complexes. This rotation does not affect conserved immunity protein interactions with the endonuclease but results in different regions of the specificity helix being presented to the enzyme.

Mechanism and cleavage specificity of the H-N-H endonuclease colicin E9.

Colicin endonucleases and the H-N-H family of homing enzymes share a common active site structural motif that has similarities to the active sites of a variety of other nucleases such as the non-specific endonuclease from Serratia and the sequence-specific His-Cys box homing enzyme I-PpoI. In contrast to these latter enzymes, however, it remains unclear how H-N-H enzymes cleave nucleic acid substrates. Here, we show that the H-N-H enzyme from colicin E9 (the E9 DNase) shares many of the same basic enzymological characteristics as sequence-specific H-N-H enzymes including a dependence for high concentrations of Mg2+ or Ca2+ with double-stranded substrates, a high pH optimum (pH 8-9) and inhibition by monovalent cations. We also show that this seemingly non-specific enzyme preferentially nicks double-stranded DNA at thymine bases producing 3'-hydroxy and 5'-phosphate termini, and that the enzyme does not cleave small substrates, such as dinucleotides or nucleotide analogues, which has implications for its mode of inhibition in bacteria by immunity proteins. The E9 DNase will also bind single-stranded DNA above a certain length and in a sequence-independent manner, with transition metals such as Ni2+ optimal for cleavage but Mg2+ a poor cofactor. Ironically, the H-N-H motif of the E9 DNase although resembling the zinc binding site of a metalloenzyme does not support zinc-mediated hydrolysis of any DNA substrate. Finally, we demonstrate that the E9 DNase also degrades RNA in the absence of metal ions. In the context of current structural information, our data show that the H-N-H motif is an adaptable catalytic centre able to hydrolyse nucleic acid by different mechanisms depending on the substrate and metal ion regime.

NMR study of Ni2+ binding to the H-N-H endonuclease domain of colicin E9.

Ni2+ affinity columns are widely used for protein purification, but they carry the risk that Ni2+ ions may bind to the protein, either adventitiously or at a physiologically important site. Dialysis against ethylenediaminetetraacetic acid (EDTA) is normally used to remove metal ions bound adventitiously to proteins; however, this approach does not always work. Here we report that a bacterial endonuclease, the DNase domain of colicin E9, binds Ni2+ acquired from Ni2+ affinity columns, and appears to bind [Ni(EDTA)(H2O)n]2- at low ionic strength. NMR was used to detect the presence of both Ni2+ coordinated to amino acid side chains and [Ni(EDTA)(H2O)N]2-. Dialysis against > or =0.2 M NaCl was required to remove the [Ni(EDTA)(H2O)n]2-. The NMR procedure we have used to characterize the presence of Ni2+ and [Ni(EDTA)(H2O)n]2- should be applicable to other proteins where there is the possibility of binding paramagnetic metal ions that are present to expedite protein purification. In the present case, the binding of Ni2+ seems likely to be physiologically relevant, and the NMR data complement recent X-ray crystallographic evidence concerning the number of histidine ligands to bound Ni2+.

Structural parsimony in endonuclease active sites: should the number of homing endonuclease families be redefined?

Homing endonucleases are classified into four families based on active site sequence motifs. Through structural comparisons we have found structural similarities between the endonuclease domain of colicin E9, an H-N-H motif-containing enzyme, and both the non-specific nuclease from Serratia and I-PpoI, a His-Cys box-containing homing endonuclease. Our comparison identifies conservation at the heart of all three enzyme active sites and so argues for a re-classification of H-N-H and His-Cys box homing endonucleases as a single family. We suggest the 'betabetaalpha-Me family' of homing enzymes to reflect the three elements of secondary structure and the metal ion that define the motif.

Long-term experience in percutaneous transluminal dilatation of renal artery stenosis.

Percutaneous transluminal dilatation was attempted in 65 patients with renovascular hypertension. In five cases (8 percent), percutaneous transluminal dilatation could not be performed for technical reasons. In the remaining 60 patients (35 with atherosclerotic stenosis and 25 with fibromuscular dysplasia), both mean systolic and diastolic pressure fell immediately after percutaneous transluminal dilatation and remained significantly lower for a period of up to five years. Cure rates after a mean control period of 21.6 months were higher in patients with fibromuscular dysplasia (50 percent) than in those with atherosclerotic stenosis (29 percent). Improvement of blood pressure was observed in 32 percent of patients with fibromuscular dysplasia and in 48 percent of patients with atherosclerotic stenosis. Follow-up angiography in 33 cases showed occlusion of the dilated artery in two patients and recurrence of slight renal artery stenosis in nine patients. Successful redilatation could be performed in five of these cases. Furthermore, renal vein renin determinations were only of limited diagnostic or prognostic value. These results document the good long-term effect of percutaneous transluminal dilatation in patients with renal artery stenosis. Percutaneous transluminal dilatation should, therefore, be the favored procedure in patients with renovascular hypertension.

Altered calcium and sodium metabolism in red blood cells of hypertensive man: assessment by ion-selective electrodes.

Free intracellular calcium [Ca2+]i, sodium [Na+]i and potassium [K+]i were assessed in freeze-thawed human red blood cells (RBC) by ion-selective electrodes. After metabolic depletion by 30 mM 2-desoxy-glucose, [Ca2+]i increased faster and to significantly higher values in RBC from 16 patients with mild to moderate essential hypertension (mean diastolic blood pressure 111 +/- 10 mmHg) than in the RBC of 24 normotensives. The rate of [Ca2+]i increase was 7.0 +/- 3.6 versus 3.7 +/- 4.0 mumol/h/l cells (P less than 0.01) for the first 24 h and 8.1 +/- 4.8 versus 6.4 +/- 3.5 mumol/h/l cells for the following 24 h. [Na+]i before and after 24 h incubation was significantly higher in hypertensives, whereas basal [Ca2+]i and [K+]i before and after incubation were the same in both groups. After Ca loading by ionophore A 23187, the maximum rate of [Ca2+]i extrusion was not significantly lower in intact RBC from hypertensives than in those from normotensives (59.5 +/- 7.8 versus 87.9 +/- 18.1 mumol/min/l cells). These results indicate disturbances in RBC Ca metabolism similar to those observed earlier for Na and K. If generalized, the defect could lead to raised [Ca2+]i in smooth muscle and sympathetic nerve tissue, thus causing increased vascular tone and probably catecholamine release with subsequent arterial hypertension.

Severe thrombocytopenia and response to corticosteroids in a case of nephropathia epidemica.

Nine days after working in the woods, a previously healthy 32-year-old man fell seriously ill. His symptoms included high fever, chills, diffuse myalgia, severe headache, and back pain. On the fifth day of onset of symptoms, blood tests showed creatinine levels of 5.4 mg/dL accompanied by marked proteinuria. After admission to the hospital, a diagnosis of nephropathia epidemica (NE) caused by Puumala virus was made using solid-phase enzyme-linked immunosorbent assay (ELISA). The patient gradually recovered renal function without requiring dialysis. However, he surprisingly experienced a sharp decline in platelet count to a minimum of 2,000/microL with concomitant occurrence of petechiae and conjunctival hemorrhage. Prednisolone was initiated, resulting in a swift rise in platelets. Six days later, when the medication was withdrawn, a sharp decrease in platelets recurred. The steroids were then readministered for the next 3 months, thus reestablishing a stable platelet count. The immediate rise of platelets after administration of prednisolone supports the pathophysiological view of hantavirus infection as an immunologically mediated disease. Corticosteroids in the treatment of hantavirus-associated thrombocytopenia might need further systematic evaluation.

Effects of L-carnitine on leukocyte function and viability in hemodialysis patients: A double-blind randomized trial.

Excess morbidity and mortality among long-term hemodialysis patients because of infectious complications is partly caused by an impairment of cellular immune defense. We hypothesized this impairment is related to an abnormal carnitine metabolism also present in these patients. In a double-blind, randomized, placebo-controlled trial, we investigated the effect of L-carnitine on phagocytic function and viability of blood leukocytes in 17 patients undergoing maintenance hemodialysis. After an observation period of 1 month, the patients received either 10 mg/kg of L-carnitine or placebo intravenously at the end of each hemodialysis session over a period of 4 months. Leukocyte oxidative metabolism was measured by means of luminol-enhanced chemiluminescence and superoxide generation after stimulation with Staphylococcus aureus or phorbol myristate acetate. Killing capacity and phagocytosis of radiolabeled staphylococci were determined. A lactate dehydrogenase (LDH) release test was applied to assess cell viability. We were unable to show an effect of L-carnitine on phagocytic function and viability in vivo. Several clinical parameters were observed during the trial. No statistically significant differences concerning dialysis-related morbidity, anemia, or reduction of blood urea nitrogen and creatinine levels were detected. Additionally, we tested the effect of L-carnitine on phagocytic function after in vitro incubation of blood leukocytes, which also showed no changes. LDH release was decreased, indicating an improved viability of these cells. The latter results were found after in vitro incubation of cells, but could not be confirmed in vivo. In summary, we could not show beneficial effects of L-carnitine administration in hemodialysis patients for the dosage and duration of treatment stated, either on phagocytic function and viability or on the clinical and biochemical parameters observed.

Serum and dialyzate concentrations of intraperitoneal cephalothin in patients undergoing continuous ambulatory peritoneal dialysis.

The pharmacokinetics of cephalothin sodium were studied in seven patients with chronic renal failure undergoing continuous ambulatory peritoneal dialysis. 100 mg of cephalothin per liter dialyzate were administered intraperitoneally during nine dialysis cycles with 2 liters of dialysis fluid per cycle. Serum levels of the antibiotic, measured microbiologically during the first, fifth and ninth dwell time, revealed peak values of 3.5 +/- 1.7 mg/l, 5.6 +/- 2.2 mg/l and 5.3 +/- 2.5 mg/l, respectively. The mean concentration in the dialysis outflow was 23.6 +/- 15.6 mg/l (range: 2.0-78.7 mg/l). Intraperitoneally administered cephalothin is well tolerated. Serum levels exceeded the minimal inhibitory concentrations of most gram positive bacteria causing peritonitis in these patients.

Effect of pindolol and propranolol on plasma renin and aldosterone in patients with renal allograft.

To investigate the effect of propranolol and pindolol on renin and aldosterone secretion, blood samples of 12 nephrectomized kidney transplant recipients were taken after 1 hour in supine position and 30 and 60 minutes after posture change. This procedure was repeated after 4 days under pindolol (3 X 5 mg/day) or propranolol (4 X 40 mg/day). Both pindolol and propranolol suppressed the significant orthostatic rise of plasma renin activity (PRA) seen without medication. Pindolol increased basal PRA markedly, whereas basal PRA under propranolol was the same as without betablockers. Plasma aldosterone (PA) showed significant orthostatic rise under all conditions and thus did not parallel PRA under betablockers. Suppression of PRA response to posture change by betablockers indicates that circulating catecholamines may be involved in orthostatic PRA regulation. The intrinsic sympathetic activity of pindolol results in an increase of basal PRA. In nephrectomized renal transplant recipients, postural PA changes do not seem to be triggered by PRA.

Control of plasma aldosterone during chronic hemodialysis.

To investigate the effect of chronic hemodialysis (CH) on adrenal aldosterone release plasma aldosterone (PA), plasma renin activity (PRA), plasma cortisol (PC) and the serum concentrations of potassium (K) and sodium (Na) were measured before and at monthly intervals up to 26 months after initiation of CH in 42 patients with terminal renal failure. Body weight (BW), systolic (BPs) and diastolic (BPd) blood pressure were determined simultaneously. With 2 exceptions PA, PRA and PC as well as BW, BPs and BPd showed no significant changes. Following month 2 K was always significantly higher than the starting value while significantly higher Na values were observed in 12 of 26 different test periods (P less than 0.05--less than 0.001). Correlation analysis between the various parameters determined in this study revealed in 16 of 26 different months a significant relationship between PA and PRA (P less than 0.05--less than 0.001) and as expected in 20 of 26 between BPs and BPd (P less than 0.05--less than 0.001). Only at times were punctual correlations seen between any of the remaining parameters. Our results demonstrate that the prime influence of the renin angiotensin system on PA remains unaltered during CH. We conclude that the observed punctual correlations between the various parameters determined in this study are random and do not reflect a true relationship.

Platelet aggregation and beta-thromboglobulin levels in nephrotic patients with and without thrombosis.

Platelet aggregation and beta-thromboglobulin levels were studied in 17 patients with the nephrotic syndrome. Thrombosis or thromboembolic complications occurred in 4 of these patients with serum albumin levels below 2 g/100 ml. Pathologic platelet aggregation assessed by estimating alpha 2-angle values derived from platelet aggregation curves was seen in the 4 patients with thromboembolic complications (alpha 2-angle 69.5 degrees +/- 10.1 degrees), whereas patients without thrombosis showed normal alpha 2-angle values (less than 30 degrees) with only one exception. In addition, patients with thromboembolic complications demonstrated significantly elevated beta-thromboglobulin levels, when compared with those not having thrombosis or thromboembolic complications (76.8 +/- 14.3 ng/ml vs 44.8 +/- 8.6 ng/ml, P less than 0.001). The decrease in serum albumin concentration showed an inverse relationship with both, alpha 2-angle values (r = -0.82, P less than 0.001) and beta-thromboglobulin levels (r = -0.83, P less than 0.001) indicating a regulatory role of serum albumin in platelet aggregation. We conclude, that altered platelet aggregation as well as hypercoagulability may be involved in the pathogenesis of thrombosis and thromboembolic complications in the course of the nephrotic syndrome.

Uremic pruritus in patients on hemodialysis or continuous ambulatory peritoneal dialysis (CAPD). The role of plasma histamine and skin mast cells.

Fifty-four uremic patients (26 patients were maintained on continuous ambulatory peritoneal dialysis [CAPD] and 28 on hemodialysis [HD]) were screened for pruritus and plasma histamine. 50% of the patients on CAPD and 64.3% of patients on HD complained of current itching. The extent of itch, assessed by a score, was not significantly different between HD and CAPD patients. Plasma histamine levels showed no significant difference between CAPD and HD patients and no correlation between plasma histamine level and the extent of pruritus could be demonstrated. In six patients on CAPD and 9 patients on HD plasma histamine levels were determined before and three months after initiation of dialysis treatment; no substantial change could be observed. In some patients skin biopsies were obtained from the gluteal region in order to determine the number of skin mast cells. The number of mast cells did not show a significant difference between controls (n = 12), uremic patients before initiation of dialysis treatment (n = 8), patients on CAPD (n = 11) and patients on HD (n = 13). There was no relationship between the level of plasma histamine, the number of skin mast cells and the extent of pruritus in uremic patients.

Problem cases in renovascular hypertension.

The clinical course and response to therapy of 16 patients with various complex forms of renovascular hypertension were investigated. Reconstructive surgery and/or transluminal dilatation was either ineffective (n = 5) or could not be performed for technical reasons (n = 11). The group contained 7 patients with multilocular fibromuscular disease involving both renal arteries, two cases with multiple arteriosclerotic vascular occlusions, 3 patients with branch renal artery aneurysms, 3 with renal artery stenosis in a solitary kidney and one patient with renal artery stenosis and contraction of the contralateral kidney due to a non-vascular cause. With antihypertensive treatment, particularly with the angiotensin converting enzyme inhibitor captopril (n = 7), blood pressure could be reduced from 214 +/- 40/124 +/- 23 mm Hg to 145 +/- 23/88 +/- 9 mm Hg (P less than 0.001). In 11 of the 16 patients (69%) the values decreased to less than 160/95 mm Hg. These results suggest that, in complex forms of renovascular hypertension, antihypertensive treatment may be a potent therapeutic alternative if surgery and/or transluminal dilatation can not be performed or seem to have too high a risk.